1. Field of the Invention
This invention relates to an apparatus for pivoting a front seat of a two-door automobile forward, so that the backrest is tilted forward when someone steps into or out of the rear seating compartment.
2. Description of the Prior Art
As is well known, the front seat 1 of a two-door automobile has a backrest adjusting apparatus 2, as shown in FIG. 1, which makes it easy for passengers to reach the rear seats.
When a inclining handle 3 at the side of the front seat 1 is pulled up, a catch disengages from a ratchet (not shown) of an upper arm 4, so that a backrest 5 thereof tilts forward. This tensions a base end 7 of a cable 6, shown in FIG. 3, connected to the upper arm 4. As a result, the cable 6, guided through the outer cable 8, pulls and rotates upward a lock lever 10 of which the upper end is pivoted about one of a pair of upper rails 9 of seat tracks that support the seat 1. This in turn separates a hook 10' of the lock lever 10 from a notch 12' in a lock plate 12 which is secured to one of the lower rails on which the upper rail 9 slides.
At the same time, another lock lever 10' attached to the other upper rail 9' paired with the first rail 9 also is rotated by the lock lever 10 together with a relay cable 13.
The seat 1 can then be slid forward by the tension of helper springs (not shown) along the upper rails 9, 9'.
In a seat provided with a walk-in apparatus 2 of this kind, for safety's sake, the backrest 5 is locked in the tilted position by a locking mechanism (not shown) to prevent anyone sitting on the front seat while the seat is in the "walk-in" position.
In the conventional walk-in apparatus, even though the backrest is locked when in the "walk-in" position, unlocking of the backrest is not necessarily limited to when the seat is slid back to a "slide-lock" position. This results in the disadvantage that, when the automobile moves off suddenly with someone sitting in the front seat, the seat could move backward because the upper rails are in sliding engagement with the lower rails.
This problem can be overcome by releasing the lock of the seat back at the seat "slide-lock" position when the seat is being slid back.
It would be safer if the seat back could be locked when it is tilted forward and the seat is advanced even a short distance from the "slide-lock" position.
However, since in a conventional walk-in apparatus the position of the slide-lock provided by the notch 12' in the lock plate 12 and the hook 10' of the lock lever 10 is restricted to only one point, it is very difficult to make the "slide-lock" position, at which the seat is locked it has been slide back, match exactly the "backrest-lock" position, because of machining errors and assembly errors.
Even if a correct setting is obtained at which the "slide-lock" position and the "back-lock" position match, the setting could shift with time because of vibration and other causes.